There is not much you can do physically in the last two weeks to improve your performance for the marathon, but there are lots of mistakes you can make that could take from your performance.
Your training may have not gone fully to plan and you may think you can probably squeeze in another long run, but don't, it's time to rest up and ease back from your training. This is a time to really enjoy the result of all your work and appreciate what it feels like to be in great physical health.
The aim of the last two weeks before the marathon is to reduce the miles and fine-tune the body. It is a difficult part of the preparation to keep the mind occupied, but remember, the less running done at this stage the better.
Keep your mind occupied so that you are not thinking too much about the race and wasting energy. Don't change anything with your diet and just because you are going to run a marathon does not mean you can eat everything in sight as this will put stress on your intestine.
Avoid caffeine and alcohol as both will cause you to be dehydrated, and drink more water than normal. You can avoid dehydration by being well hydrated going into the marathon. If you want to get a pre-race deep-tissue massage, do it at least a week to 10 days before the marathon as this can have the same effect as a hard workout on your muscles.
Running a marathon requires mental strength as much as it does physical fitness.
One of the biggest mistakes marathoners make is starting out at too fast a pace. It's tempting to go out fast because you will feel strong and rested, and a slower pace will almost feel too easy. If you go out too fast, you will burn through a lot of your stored energy too early and your legs will feel tired sooner.
It is always advisable to run the first half slower than the second half. Be wise and don't panic if a lot of people are passing you. Run at your own planned pace and the chances are you will be passing them out at a later stage. Remember, the race does not start until the 20-mile mark if racing or aiming for a time is what you are after. But I appreciate that, for many people, the participation and completion of the race is the only goal.
Break the race up into smaller segments as it will make the distance feel more manageable. Your mental toughness will be challenged at different stages throughout.
Don't give into discomfort and self-doubt. There will come a stage in the marathon where you have to allow your mind take over from your body and you will need to dig deep for extra strength.
I wrote here before about the severe stomach cramps I experienced during the second half of the London Marathon. I thought about all the sacrifices I had made to get to this point and that I had worked hard through fatigue and discomfort during my training runs and I was going to do it again. This positive thinking got me to the finish line.
You need to adapt a strong state of mind. Remember all the work you have put into this and how rewarding it will be when you cross the finish line. Stay relaxed, maintain your focus and visualise achieving everything you hoped to accomplish for the race and you will overcome your mental battles. Marathons are certainly all about mind and body.